Ultron should definitely be a man in a suit. If gives the performance/character a much more tangible feel, and is almost certainly cheaper

They can do it like the Iron Man suits, with CGI "fillings"

If they don't want to force the actor to go full-on C-3PO

Also IIRC the ILM guys were saying it was easier to work with the CGI "fillings", as it improves the actor's range of motion so that a fully CGI double wasn't often necessary, while keeping a large portion of the costume completed for them

Nathan Fillion would make a good Simon Williams/Wonder Woman, with Jason Bateman playing Eric Williams/The Grim Reaper.

In my Avengers movie idea, Williams Munitions are picking up the slack since Stark Enterprises got out of the weapons business, building things for SHIELD, America and America's allies using Ionic energy as a power source. Simon is a cheerful movie buff who uses some of his millions to produce fantasy movies (Arkon, Marvel's Conan expy). Eric is dour and has created "reapers" for SHIELD.

Nathan Fillion would make a good Simon Williams/Wonder Woman, with Jason Bateman playing Eric Williams/The Grim Reaper.

In my Avengers movie idea, Williams Munitions are picking up the slack since Stark Enterprises got out of the weapons business, building things for SHIELD, America and America's allies using Ionic energy as a power source. Simon is a cheerful movie buff who uses some of his millions to produce fantasy movies (Arkon, Marvel's Conan expy). Eric is dour and has created "reapers" for SHIELD.

....I'm not sure I'm comfortable with Fillion playing a cross-dresser from a different comic-book universe.

"I knew there was something wrong, it just took a while to dawn on me, or maybe I was just afraid to think it, but you survived the destruction because you caused it. Raina wasn't the only one changed in there, and I'm pretty sure the DNA results that I'm running right now will confirm that there's nothing wrong with the data in my head Skye, there's something wrong with you."